As an extension of our human cDNA project for accumulating sequence information on the coding sequences of unidentified genes, we here present the entire sequences of 100 cDNA clones of unidentified genes, named KIAA1673-KIAA1772, from three sets of size-fractionated cDNA libraries derived from human adult whole brain, hippocampus, and fetal whole brain. The average sizes of the inserts and corresponding open reading frames of cDNA clones analyzed here were 4.9 kb and 2.7 kb (corresponding to 895 amino acid residues), respectively. By computer-assisted analysis of the deduced amino acid sequences, 44 predicted gene products were classified into five functional categories of proteins relating to cell signaling/communication, nucleic acid management, cell structure/motility, protein management, and metabolism. Furthermore, the expression profiles of the genes were also studied in 10 human tissues, 8 brain regions, spinal cord, fetal brain and fetal liver by reverse-transcription-coupled polymerase chain reaction, the products of which were quantified by enzyme-linked immunosorbent assay.